It could be a redirect from somewhere else in your user folder.

The folder DropBox reappearing makes me believe something else expects the folder to be there. It's just a shortcut and in all that was happening, it could have been created by accident. As for the shortcut in Documents that pointed to Downloads, you can most likely just delete it. That's good and I believe it could be left that way. Regardless, you were able to redirect Downloads and they actually go to Downloads stuff, and none of that is under DropBox. The Downloads stuff ended the way it should, but I think it was the long way. I think DropBox used a junction to put Downloads where it wanted them to be. In cases of multiple hard drives, a junction can actually be on a different disk. But a junction is a way to create an item that looks and acts like a folder, but it really redirects to some other folder. I hate to get a technical on people when all they want is to get the problem sorted so they can move on with their things to do. Once you have the Downloads on My PC working properly with your newly created folder, you can safely remove the older Downloads, which could really be a junction. Then use the steps above to change the Downloads in My PC to a new location and use the new name. Create this folder under your personal folder in Users.

Something like NewDownloads or Downloads2, etc. The simplest way to get around this is to create a new folder for downloads but name something different. And it is possible DropBox made a junction for Downloads and that is the thing you are hitting. It is possible in Windows to create folder names that are actually junctions.

How to get rid of dropbox